Explosive-cap protector.



CHARLES ALLISON, F GLENDALE, CALIFORNIA.

ExPLosIvE-CAP PROTECTOR.

Specification of Letters Patent.

Patented Dee. 14, 1915.

Applica-tion filed liarch 16, 1915. Serial No. 14,805.

To all whom t may concern:

Beit known that I, CHARLES H. ALLIsoN, a citizen of the United States, residing at Glendale, in the county of Los Angeles, State of California, have invented new and useful Improvements in Explosive-Cap Protectors, of which the following is a specificatiorn This invention rela-tes to a protector for explosive caps and to improvements upon the explosive cap protection for which Patent No. 1,094,692 was issured to me on April 28, 19H; and the present improvement coni sists particularly in certain changes designed toadapt my protector more efliciently for use in extremely high water pressures. In some instances, where using the protection described in my said patent, it has been.

found that the water pressure at a mile or more in depth has been sufficient to crush the cap within theprotecting envelop. The

caps are never completely filled with the detonating substance, some air voids always being left within the caps; and I have found that under extremely heavy pressures, as of depth of 'a mile or more in water, the

"caps themselves may be compressed and premature explosion may possibly occur or about the cap; and then, while the envelopI is still plastic, it is inserted in a casingof glass or other suitable material, being rpressed into the casing so that there are no voids whatever within the casing. The casing, preferably in halves, is held together around the envelop and cap by any suitable means. I prefer to halve the casing and to hold it together by a casing of rubber tape; but this may be as desire-d. The material of the casing is of great pressiire resisting strength, having notonly its own pressure resisting strength but being supported from the inside by having the solid mass of asphalt or other material `filling its entireinterior without any voids. By this construcenvelop around the cap and also have the Y advantage of'a physically strong casing which will support a great fluid pressure,

but which is fragile and easily broken by detonation on theinside. f

I have shown the improved form of my protector in the accompanying drawings, in which- Figure 1 is a longitudinalr section of a protector inclosing a bundle of caps, Fig.- 2 is ai transverse section of the same, F ig.` 3 is an exterior view of the same and Fig. 4 is a longitudinal section showing a modified form of' the large cap.

In the drawings, the numeral 10 designates caps, which may be associated in any number in a bundle, and l1 designates the envelop of asphalt or any other suitable material which is kneaded about the cap protector inclosing a single and into spaces between them, forming av voidless mass which itself is practically incompressible. I prefer to use asphalt. for this pp rpose for the reasons set f'orth in my former patent; because the asphalt is hard and will withstandrgreat compressive pressure, and is brittle and easily disrupted by detonation from within, and 'can be rendered plastic by heating to temperature which cannot detonate the cap.

The casing 12 is made preferably in two ,Y halves separated on a central longitudinal plane. The casingis preferably cylindrical with rounded ends; and at the ends there are tw-o apertures for the passage of thewires l-l leading to the caps. The halves of the casing may be joined by such a joint as is shown at 15 in Fig. 2, so that the halves are registered in correct position. This casing is preferably made of' glass or other similar mate-rial, which will offer great resistance to fluid compression from the outside but which is easily disrupted by detonation from the inside. l

The asphalt envelop Il is worked around the aps until it assumes approximately the shape and size of the interior of the casing, preferably slightly smaller lthan the interior. The mass of the envelop is still plastic when it is inserted in the casing. To add to the plasticity of the exterior part oflthe envelop, the kneaded mass is dippedin heated',-

`liquid asphalt just prior to being inserted in` the casing; and this heated liquid asphalt is sufficiently plastic and fluidlto cause an absolutely voidless fit of theasphal'tmass withtion I have the advantage of therkneaded" inthe casing;A :Thpkmg proted by the thick mass of asphalt around it, at a comparatively low temperature, the high temperature Vot' the fluid asphalt adhering l to the outside of the mass does not reach the cap. AAfter the heated mass is dipped in for reception of the halves of the casing.

After the casing has been placed around the mass of asphalt. and the excess asphalt .squeezed out through the end openings, the asphalt is kneaded about the end opening 20 and about the. Wires projecting therethrough and a covering is vthen placed around the Whole, as shown at 1G. This covering-may preferablybe a rubber casing tightly drawn around lthe casing and around the ends where '-the wires emerge, lto physically protect the 'casing from breakage and also to hold `the halves of the casing together.

In Figs. 1, 2, and 3 I have illustrated a form o'fmyfprotector to hold. a bundle of 9.0 small caps; While in Fig. 4 I have illustrated a form which holds a single large cap 10a. The-construction is essentially the same as hereinbefore described, excepting that the easing' 12a is longer and more slender than that designed to hold a bundleoic caps. This "form of `protector is especially useful in operations Where rotary drilling rigs are used, Where itif' necessary to lower the explosive charge tl )ugh the hollow drill pipe and drill steir In my provcdform of protector as herein descril ed, I retain all of the advantages of my former protection, together with the advantageous feature of the casing 12 which y. extremely heavy water' pressure. vThe casing is not only strong in itself, but "it is supported by the solid incompressiblemass of asphalt inits interior; andthe water pressure from the outside is partially transmitted to the interior of the casing through the asphalt extending through the apertures 13, thus partially balancing the pressures inside and outside the glass casing. The glass casing, although it thus protects the cap from deformation and from being crushed, does not materially damp' the detonativel action have hereunto subscribed my name this 10th of the cap, being fragile and easily broken.

Having described my invention, I claimz- 1. An explosive cap protector, comprising an envelop of Water proof material kneaded about the cap in a solid mass, a casing surrounding said envelop, ,said casing being rotects the caps from rupture or distortionv parted so that the kneaded envelop ma be tted Without voids into the casing, an an exterior covering aro'und the casing.

2. An explosive cap protector, comprising i an envelop of Water proof material kneaded 3. Anexplosive cap protector, comprising an envelop of asphalt kneaded about the cap,

laparted glass casing into which the envelop is inserted While plastic, and a covering over l the glass casing.

L1. An explosive cap protector, comprising an enve op of asphalt kneaded about the cap, aparte( "glass casing into which the envelop is inserted While plastic, and a taping surrounding the glass casing to hold the halves together and to'protect it from breakages.

A5. An explo/sive cap protector, comprising an envelop of water proof material kneaded about the cap in a solid mass, and a casing surrounding the kneaded mass, said casing being parted so that the kneaded Inassmay4 be fitted thereinto without voids.A

6. An explosive cap protector, comprising f an envelop of water proof'material kneaded about the cap in a solid mass, and al casing of vitreous material surrounding the vkneaded mass, said casing being parted so that the kneaded `mass maybe fitted thereinto Without voids.- v y 7. An explosive cap protector, comprising an envelop of water proof material kneaded about the cap in a solid mass, and a thick rounded casing of vitreous material surrounding the kneaded mass, said casing bey ing parted so that the kneaded mass may be fitted thereinto without voids.

8. An explosive cap protector, comprismg an envelop of water proof material and an exterior casing of vitreous material.

9. An explosive cap protector, comprisin an envelop of water proof plastic material formed about the cap While plastic, and an ,exterior casing of vitreous material. 710; An explosive cap protector, comprlsing an envelop of water proof material and a thiclc exterior casing of a vitreous material.

11. An explosive cap protector, comprising an envelop ot water prooi:I plastic material formed about the cap while plastic, and a rounded thick exterior casing of vitreous material.

In Witness that I claim the foregoing l day of March 1915,

CHARLES H. ALLISON.

.Witnesses:

JAMES T. BARKEL'EW,

ELWooD BARKELEW 

